Thirty-five preterm (< 1500 g) infants were fed preterm human milk (PHM) supplemented with either powdered fortifier (PF) or liquid supplement (LS). Bone mineral content (BMC) of the distal third radius was measured by photon absorptiometry. Biochemical indices of nutritional and bone status were obtained every 2 weeks. The initial BMC for both feeding regimens were similar. BMC did not change over the study period for infants fed LS. Infants fed PF had BMC values greater than LS infants at weeks 2 and 4 of study. Only infants fed PF had BMC values that demonstrated a consistent increase. Serum total protein and phosphorus values were greater for PF infants at week 4 than LS infants. Weight, length, occipital-frontal circumference (OFC) gains, serum albumin, alkaline phosphatase, calcium, and vitamin D levels were similar in both groups. We conclude that products used to "enrich" PHM are adequate to meet the growth needs of the preterm infant. However, we found that infants fed the powdered fortified preterm human milk had higher bone mineralization than those fed the liquid supplemented human milk.